KR20170049798A - Organic light emitting display device, and the method for driving therof - Google Patents

Abstract

An organic light emitting display device according to the present invention comprises a display panel having a plurality of sub pixels, a source driver, a timing controller, and a gamma reference voltage generator for supplying a gamma reference voltage. Therefore, it is possible to mitigate fluctuation of a data voltage of the non-sensing sub pixel by changing a black data voltage, and thereby prevent deterioration of screen quality. A driving method of the organic light emitting display device according to the present invention comprises the steps of: determining whether a sensing period, sensing a characteristic value of a driving transistor disposed in each sub pixel, is sensed; and when the sensing period is confirmed, changing a gamma reference voltages based on the generation of gamma voltages to change a black data voltage. Thereby, the fluctuation of the data voltage of the non-sensing sub pixel is mitigated to prevent the deterioration of screen quality.

Description

TECHNICAL FIELD [0001] The present invention relates to an organic light emitting diode (OLED) display device,

The present invention relates to an organic light emitting display and a driving method thereof.

2. Description of the Related Art [0002] In recent years, an organic light emitting diode (OLED) display device that has been widely known as an organic light emitting display device has advantages of high response speed, high luminous efficiency, luminance, and viewing angle by using an organic light emitting diode (OLED)

In such an organic light emitting diode display, subpixels including an organic light emitting diode and a driving transistor for driving the organic light emitting diode are arranged in a matrix form, and the brightness of the subpixels selected by the scan signal is controlled according to data gradation.

In such an OLED display device, each circuit element such as an organic light emitting diode and a driving transistor in each sub-pixel has a characteristic value (e.g., threshold voltage, mobility, etc.).

However, the circuit characteristics of each circuit element in each subpixel may be degraded as the driving time increases, and the luminance characteristic of the corresponding subpixel may be changed in accordance with the characteristic value change.

Accordingly, techniques for sensing and compensating characteristic values for circuit elements within each sub-pixel have been developed. Particularly, although compensation of the characteristic value of the driving transistor is compensated for by the compensation technique, the picture quality may be lowered due to other causes.

For example, when a black data voltage applied to a non-sensing sub-pixel during a sensing period sensing a characteristic of a circuit element fluctuates a data voltage retained for displaying an image in a display period, to be.

As described above, the organic light emitting display device may degrade the picture quality due to not only the luminance degradation due to deterioration of the circuit elements in the subpixel but also other causes. Therefore, various reasons for degrading the picture quality are analyzed and various techniques Is required.

In the present invention, by changing the black data voltage supplied to the sensing sub-pixel and the non-sensing sub-pixel during the sensing period differently from the driving black data voltage supplied to the display period, the data voltage fluctuation of the non- And to provide a driving method thereof.

According to an aspect of the present invention, there is provided an OLED display device including a display panel in which a plurality of data lines and a plurality of gate lines are arranged and a plurality of subpixels are arranged in a matrix type, A timing controller for controlling the source driver, and a gamma reference voltage generator for supplying a gamma reference voltage, wherein the source driver generates a gamma reference voltage based on the gamma reference voltage, Wherein each of the plurality of subpixels includes an organic light emitting diode and a driving transistor for driving the organic light emitting diode, wherein during a sensing period for sensing a characteristic value of the driving transistor, The gamma reference voltage generator changes the gamma reference voltage, The source driver generates a black data voltage according to the changed gamma voltage and supplies the generated black data voltage to the subpixel by changing the gamma voltage for the black data corresponding to the subpixel based on the changed gamma reference voltage, It is possible to mitigate the fluctuation of the data voltage of the non-sensing subpixel, thereby preventing the degradation of the screen quality.

A method of driving an organic light emitting display according to the present invention includes a display panel in which a plurality of data lines and a plurality of gate lines are arranged and a plurality of sub pixels are arranged in a matrix type, And a timing controller for controlling the source driver, the driving method comprising the steps of: determining whether the display panel is a display period for displaying an image or a sensing period for sensing a characteristic value of a driving transistor disposed in each subpixel Changing the gamma reference voltages based on the generation of the gamma voltages to change the gamma voltages for the black data corresponding to the subpixels when the sensing period is determined, And generating and supplying a data voltage to the subpixel, It is possible to mitigate the fluctuation of the data voltage of the non-sensing subpixel, thereby preventing the degradation of the screen quality.

The organic light emitting display device and the driving method thereof according to the present invention can change the black data voltage supplied to the sensing subpixel and the non-sensing subpixel during the sensing period differently from the driving black data voltage supplied to the display period, So that the deterioration of the picture quality can be prevented.

1 is a schematic system configuration diagram of an organic light emitting diode display according to the present invention.
FIGS. 2A and 2B are exemplary views illustrating an organic light emitting display sub-pixel structure according to embodiments of the present invention. Referring to FIG.
3 is a view illustrating a connection structure of a sensing line and sub-pixels of an OLED display according to the present invention.
4 is a view for explaining the reason why a data voltage of a non-sensing sub-pixel varies during a sensing period of the OLED display.
5 is a diagram illustrating a sensing period control system of an OLED display according to an exemplary embodiment of the present invention.
FIG. 6 is a diagram illustrating a linear gamma graph of a sensing period and a display period of an OLED display according to an exemplary embodiment of the present invention. Referring to FIG.
7 is a diagram illustrating data voltages supplied to a sensing period and a display period of the OLED display according to the present invention.
8 is a view for explaining how a data voltage fluctuation in a non-sensing sub-pixel of an organic light emitting diode display of the present invention is reduced.
9 is a diagram illustrating a display period and a sensing period of an OLED display according to an exemplary embodiment of the present invention.
10 is a flowchart illustrating a method of driving an organic light emitting display according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

The shapes, sizes, ratios, angles, numbers, and the like disclosed in the drawings for describing the embodiments of the present invention are illustrative, and thus the present invention is not limited thereto. Like reference numerals refer to like elements throughout the specification. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

In the case where the word 'includes', 'having', 'done', etc. are used in this specification, other parts can be added unless '~ only' is used. Unless the context clearly dictates otherwise, including the plural unless the context clearly dictates otherwise.

In interpreting the constituent elements, it is construed to include the error range even if there is no separate description.

In the case of a description of the positional relationship, for example, if the positional relationship between two parts is described as 'on', 'on top', 'under', and 'next to' Or " direct " is not used, one or more other portions may be located between the two portions.

In the case of a description of a temporal relationship, for example, if a temporal posterior relationship is described by 'after', 'after', 'after', 'before', etc., 'May not be contiguous unless it is used.

The first, second, etc. are used to describe various components, but these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, the first component mentioned below may be the second component within the technical spirit of the present invention.

It is to be understood that each of the features of the various embodiments of the present invention may be combined or combined with each other, partially or wholly, technically various interlocking and driving, and that the embodiments may be practiced independently of each other, It is possible.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the size and thickness of the device may be exaggerated for convenience. Like reference numerals designate like elements throughout the specification.

FIG. 1 is a schematic system configuration diagram of an organic light emitting display according to the present invention, and FIGS. 2A and 2B are exemplary views of a subpixel structure of an organic light emitting display according to embodiments of the present invention.

1, a plurality of data lines DL and a plurality of gate lines GL are arranged, and a plurality of sub pixels (SPs) are arranged A source driver 120 driving a plurality of data lines DL, a scan driver 130 driving a plurality of gate lines GL, a source driver 120, A timing controller 140 for controlling the controller 130, and the like.

The timing controller 140 supplies various control signals to the source driver 120 and the scan driver 130 to control the source driver 120 and the scan driver 130.

The timing controller 140 starts scanning according to the timing implemented in each frame and switches the input image data inputted from the outside according to the data signal format used by the source driver 120, ), And controls the display driving data at an appropriate time in accordance with the scan signal.

The source driver 120 drives the plurality of data lines DL by supplying the driving data voltage Vdata to the plurality of data lines DL. Here, the source driver 120 is also referred to as a " data driver ".

The scan driver 130 sequentially drives the plurality of gate lines GL by sequentially supplying scan signals to the plurality of gate lines GL. Here, the scan driver 130 is also referred to as a 'gate driver'.

The scan driver 130 sequentially supplies the scan signals of the On voltage or the Off voltage to the plurality of gate lines GL under the control of the timing controller 140.

When the specific gate line is opened by the scan driver 130, the source driver 120 converts the image data received from the timing controller 140 into an analog data voltage and supplies the data voltage to a plurality of data lines DL.

1, the source driver 120 is located only on one side (e.g., on the upper side or the lower side) of the display panel 110 but may be disposed on both sides of the display panel 110 ). ≪ / RTI >

1, the scan driver 130 is disposed on only one side (e.g., the left side or the right side) of the display panel 110, The right side).

The timing controller 140 described above includes the vertical synchronizing signal Vsync, the horizontal synchronizing signal Hsync, the input data enable signal DE, the clock signal CLK, and the like in addition to the input video data And receives various timing signals from the outside (e.g., the host system).

The timing controller 140 may control the source driver 120 and the scan driver 130 in addition to outputting the converted video data by switching the input video data inputted from the outside according to the data signal format used by the source driver 120 A timing signal such as a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, an input DE signal and a clock signal and generates various control signals to control the source driver 120 and the scan driver 130 .

For example, in order to control the scan driver 130, the timing controller 140 generates a gate start pulse (GSP), a gate shift clock (GSC), a gate output enable signal GOE : Gate Output Enable), and the like.

Here, the gate start pulse GSP controls the operation start timing of one or more gate driver ICs constituting the scan driver 130. The gate shift clock GSC is a clock signal commonly input to one or more gate driver integrated circuits, and controls the shift timing of the scan signal (gate pulse). The gate output enable signal GOE specifies the timing information of one or more gate driver ICs.

In addition, the timing controller 140 controls the source driver 120 such that a source start pulse SSP, a source sampling clock SSC, a source output enable signal SOE, Output enable (DCS) data control signals.

Here, the source start pulse SSP controls the data sampling start timing of one or more source driver ICs constituting the source driver 120. The source sampling clock SSC is a clock signal for controlling sampling timing of data in each of the source driver integrated circuits. The source output enable signal SOE controls the output timing of the source driver 120. [

The source driver 120 may drive a plurality of data lines including at least one source driver integrated circuit (SDIC).

Each source driver integrated circuit (SDIC) includes a shift register, a latch circuit, a digital to analog converter (DAC), an output buffer, a gamma voltage generating section ), And the like.

Each source driver integrated circuit (SDIC) may further include an analog to digital converter (ADC), as the case may be.

The scan driver 130 may include at least one gate driver integrated circuit (GDIC).

Each gate driver IC (GDIC) may include a shift register, a level shifter, and the like.

Each subpixel SP disposed on the display panel 110 may include a circuit element such as a transistor.

For example, in the display panel 110, each sub-pixel SP is composed of an organic light emitting diode (OLED) and a circuit element such as a driving transistor for driving the organic light emitting diode (OLED).

The types and the number of the circuit elements constituting each subpixel SP can be variously determined depending on the providing function, the design method, and the like.

Referring to FIGS. 2A and 2B, in the organic light emitting diode display 100 according to the present invention, each sub pixel includes an organic light emitting diode (OLED), an organic light emitting diode (OLED) A driving transistor DRT and a first transistor N1 electrically connected between a first node N1 of the driving transistor DRT and a sensing line SL for supplying a reference voltage Vref, A second transistor T2 electrically connected between a second node N2 of the driving transistor DRT and a data line DL for supplying a data voltage Vdata; And a storage capacitor (Cst) electrically connected between the first node N1 and the second node N2.

The organic light emitting diode OLED may include a first electrode (e.g., an anode electrode or a cathode electrode), an organic layer, and a second electrode (e.g., a cathode electrode or an anode electrode).

The driving transistor DRT drives the organic light emitting diode OLED by supplying a driving current to the organic light emitting diode OLED.

The first node N1 of the driving transistor DRT may be electrically connected to the first electrode of the organic light emitting diode OLED and may be a source node or a drain node. The second node N2 of the driving transistor DRT may be electrically connected to the source node or the drain node of the second transistor T2 and may be a gate node. The third node N3 of the driving transistor DRT may be electrically connected to a driving voltage line DVL for supplying a driving voltage EVDD and may be a drain node or a source node.

2A, the first transistor T1 is turned on by the first scan signal SCAN1 to apply a reference voltage Vref to the first node N1 of the driving transistor DRT .

Also, the first transistor T1 may be utilized as a voltage sensing path for the first node N1 of the driving transistor DRT when turned on.

The second transistor T2 transfers the data voltage Vdata supplied through the data line DL to the second node N2 of the driving transistor DRT when the second transistor T2 is turned on by the second scan signal SCAN2 It does.

The storage capacitor Cst is electrically connected between the first node N1 and the second node N2 of the driving transistor DRT so that the data voltage corresponding to the video signal voltage or the voltage corresponding thereto is supplied for one frame time I can keep it.

The storage capacitor Cst is not a parasitic capacitor (for example, Cgs or Cgd) which is an internal capacitor existing between the first node N1 and the second node N2 of the driving transistor DRT, And is an external capacitor intentionally designed outside the driving transistor DRT.

On the other hand, as shown in FIG. 2B, the first transistor T1 and the second transistor T2 may be controlled together by a single scan signal SCAN.

That is, the first transistor T1 and the second transistor T2 are connected to the same gate line GL, and the same scan signal SCAN can be supplied to both the first transistor T1 and the second transistor T2.

The sensing lines SL electrically connected to the drain node or the source node of the first transistor T1 may be arranged for each sub pixel column or may be arranged for every two or more sub pixel columns May be arranged one by one.

For example, when one pixel is composed of four subpixels (red subpixel, white subpixel, blue subpixel, green subpixel), the sensing line SL includes four subpixel columns (red subpixel columns, Green sub-pixel columns, white sub-pixel columns, blue sub-pixel columns, and green sub-pixel columns).

In the case of the organic light emitting diode display 100 according to the present invention, as the driving time of each sub-pixel SP increases, deterioration of circuit elements such as the organic light emitting diode OLED and the driving transistor DRT Degradation can proceed.

Accordingly, inherent characteristic values (e.g., threshold voltage, mobility, etc.) of the circuit elements such as the organic light emitting diode OLED and the driving transistor DRT can be changed.

Such a change in the characteristic value of the circuit element causes the luminance change of the corresponding subpixel.

Here, the characteristic value of a circuit element (hereinafter also referred to as a " subpixel characteristic value ") may include, for example, a threshold voltage and a mobility of a driving transistor DRT, May include the threshold voltage of the transistor.

The organic light emitting diode display 100 according to the present invention includes a sensing function for sensing a characteristic value variation of a subpixel or a characteristic value deviation between subpixels and a compensation function for compensating a subpixel characteristic value using a sensing result can do.

Accordingly, the organic light emitting diode display 100 of the present invention is provided with a subpixel structure (FIG. 2A or 2B) corresponding thereto, and a compensation including a sensing and compensation structure, in order to provide a sensing and compensation function for the subpixel characteristic value. Circuit.

FIG. 3 is a view showing a connection structure of a sensing line and sub-pixels of an OLED display according to the present invention, and FIG. 4 is a diagram illustrating a reason why a data voltage of a non- Fig.

Referring to FIG. 3, the OLED display of the present invention includes a red (R) subpixel, a white (W) subpixel, a green (G) subpixel, and a blue Pixel. Each subpixel SP constituting a pixel is connected to either one of the data lines DL and to one of the gate lines GL and the four subpixels constituting the pixel are connected to one of the sensing lines SL connected in common.

Each subpixel SP of the organic light emitting display device can operate as a sensing period for sensing a characteristic value of a subpixel and a display period for displaying an image.

3, a scan signal SCAN (second transistor ON voltage) is input through a gate line GL corresponding to each horizontally adjacent subpixel SP in the sensing period The sensing data voltage Vdata_SEN is supplied to the sensing subpixel through the data line DL connected to the sensing subpixel and the sensing signal Vsen is output through the sensing line SL. The sensing subpixel is defined as a subpixel to which a sensing data voltage Vdata_SEN is supplied to sense a characteristic value change of the subpixel SP and refers to a red (R) subpixel in FIG.

In order to increase the sensing accuracy, non-sensing subpixels commonly connected to the sensing line SL are supplied with a black data voltage Vdata_B. In the present invention, the driving black data voltage Vdata_BD A high black data voltage (Vdata_B) is generated and supplied to the non-sensing subpixel to prevent the deterioration of the picture quality (see the gamma curve in Fig. 6).

3, the non-sensing subpixels refer to the white (W), green (G), and blue (B) subpixels connected in common to the sensing line SL, Green (G), and blue (B) subpixels because they are commonly connected to the red (R) subpixels, the white (W) subpixels, the green And white (W) subpixels in the column direction, green (G) subpixels, and blue (B) subpixels for blue subpixels are also included in the non-sensing subpixel.

The driving black data voltage (Vdata_BD) is a black data voltage (0 gray voltage) in the display period generated using the linear region gamma curve graph of the display period shown in FIG. Generally, since the black data voltage supplied during the sensing period also uses the linear gamma curve of the display period of FIG. 6, the driving black data voltage (Vdata_BD) is also supplied during the sensing period.

As described above, when sensing driving is performed on the organic light emitting display, the result of the sensing signal Vsen is obtained through the sensing line SL, and the process of compensating the data based on the result is performed.

However, as shown in FIG. 6, the driving black data voltage Vdata_BD is set to the lowest value among the gamma voltage ranges since it is determined by the display section linear gamma curve for expressing 0 to 255 gray levels.

If the driving black data voltage Vdata_BD supplied to the non-sensing sub-pixel is low during the sensing period, the data voltage held in the non-sensing sub-pixel is increased by the negative shift of the second transistor T2, This causes a problem of causing a streak defect in the display section.

Referring to FIG. 4, as described above, the non-sensing subpixel includes subpixels corresponding to (off-voltage) gate lines to which a scan signal (turn-on voltage) is not applied. For example, the driving black data voltage (Vdata_BD) is also applied to the white (W) subpixel in the column direction connected in common with the data line (DL) connected to the white (W) subpixel in FIG.

As shown in FIG. 4, when the scan signal (ON voltage) is not applied to the gate line (SCAN2: OFF voltage) but the threshold voltage Vth of the second transistor T2 of the non- The second transistor T2 is in a lightly turned-on state.

This causes a problem that the data voltage VN2 of the second node, which has been held for displaying an image in the display period, fluctuates through the data line DL (data mixing failure).

Particularly, the greater the difference (VN2-Vdata_BD) between the data voltage VN2 and the driving black data voltage Vdata_BD, the greater the rate of variation in which the data voltage VN2 drops in the data line DL direction. Quality degradation. Although the white (W) non-sensing subpixel in the column direction is shown in FIG. 4, the same phenomenon occurs in the green (G) and blue (B) non-sensing subpixels in the column direction.

The organic light emitting display device and the driving method thereof according to the present invention can supply the black data voltage higher than the driving black data voltage supplied to the non-sensing subpixels in the sensing period, Thereby reducing the difference in image quality.

FIG. 5 is a diagram illustrating a sensing range control system of an OLED display according to the present invention. FIG. 6 is a diagram illustrating a sensing gamut and a linear gamma graph of a display duration of the OLED display according to the present invention. 7 is a diagram illustrating data voltages supplied to the sensing period and the display period of the OLED display according to the present invention.

5, the organic light emitting diode display 100 of the present invention includes a display panel 110, a source driver 120, a timing controller 140, and a scan driver 130, A gamma reference voltage generator 503 for supplying gamma reference voltages to the source driver IC (SDIC) of the source driver 120 and a sensing interval controller 500 for controlling the gamma reference voltage generator 503 . The gamma reference voltage generator 503 may be implemented as a programmable gamma (IC).

The source driver 120 may further include a plurality of source driver ICs (SDIC), and the source driver IC (SDIC) may further include a gamma voltage generator 504 including resistive strings for voltage division. In the present invention, the sensing period controller 500, the gamma reference voltage generator 503, and the gamma voltage generator 504 may operate as one sensing period system for varying the black data voltage in the sensing period.

The sensing period controller 500 includes a sensing period checking unit 501 for checking a display period and a sensing period and a gamma reference voltage generator 503 for generating a gamma reference voltage according to the information detected by the sensing period checking unit 501. [ And a control unit 502 for changing the reference voltages RV0, ..., RV9.

The gamma voltage generator 504 generates the gamma voltages V_min corresponding to 0 to 255 gray levels by the gamma reference voltages RV0, ..., RV9 supplied from the gamma reference voltage generator 503, To V_max). The gamma voltages V_min to V_max are selected so as to correspond to the gray level values of the data (image data or sensing data or black data) supplied to the DAC disposed in the source driver IC and supplied to the timing controller 140 . By means of the selected gamma voltages, the data are converted into voltages in an analog form (gamma voltage or gradation voltage).

More specifically, as shown in FIG. 7, in the organic light emitting diode display of the present invention, the sensing data voltage (Vdata_SEN) and the black data voltage (Vdata_B) are applied to the sensing subpixel during the sensing period in the blank section And a black data voltage Vdata_B higher than the drive black data voltage Vdata_BD is supplied to the non-sensing subpixel. The blank interval may be divided based on the vertical synchronization signal Vsync and may further include a period for supplying recovery data for the sensing interval and the display interval.

In the display period, a data voltage (Vdata) for displaying an image is supplied to each subpixel. The data voltage (Vdata) includes a 0-gradation driving black data voltage (Vdata_BD).

In the present invention, a black data voltage (Vdata_B) higher than the driving black data voltage (Vdata_BD) used in the display period is generated to prevent the data voltage variation occurring in the non-sensing subpixel during the sensing period, Pixel.

To this end, in the present invention, the sensing period controller 500 is used to change the gamma reference voltages on which the sensing data voltage Vdata_SEN and the black data voltage Vdata_BD are generated in the sensing period.

5 and 6, in a display period in which an image is displayed, a gamma reference voltage generator 503 generates gamma reference voltages of RV0, ..., RV9 and supplies it to a gamma voltage generator And generates a plurality of gamma voltages corresponding to 0 to 255 grayscales.

6, the lowest gamma voltage V_min and the highest gamma voltage V_max correspond to 0 gray and 255 gray, respectively.

The lowest gamma voltage V_min corresponds to the driving black data voltage Vdata_BD supplied to each subpixel in the display period. The voltage value is 0.5 [V] equal to the lowest gamma reference voltage RV0 . On the other hand, the highest gamma voltage V_max corresponding to 255 gray levels corresponds to the highest gamma reference voltage RV9 (e.g., 16 [V]).

In the sensing period for sensing the characteristic values of the subpixels, the gamma reference voltage generator 503 generates the modified gamma reference voltages RV'0, ..., RV'9 under the control of the sensing period controller 500 And supplies it to the gamma voltage generator 504 to generate gamma voltages that are different from the gamma voltages generated in the display period.

Since the gamma reference voltages are based on the gamma voltages generated by the gamma voltage generator 504, the gamma reference voltages are changed by changing the gamma reference voltages.

As shown in FIG. 5, it can be seen that the lowest gamma reference voltage RV'0 in the sensing period is changed to be higher than the lowest gamma reference voltage RV0 in the display period. When the lowest gamma reference voltage RV'0 is changed in the sensing period, the next higher gamma reference voltages are also sequentially changed (RV'1, ... RV'9). This is because the lowest gamma reference voltage is changed from RV0 to RV'0 in the sensing period. If the voltage of RV'0 is equal to or larger than the RV1 gamma reference voltage, a linear gamma curve is not generated. Thus, if the lowest gamma reference voltage is changed (RV0- > RV'0), then the next gamma reference voltages RV'1, ... RV'9 must also be changed sequentially.

Figure 6 shows a linear gamma curve for use during the sensing period according to the present invention. It can be seen that the lowest gamma voltage V_min 'corresponding to the black data voltage Vdata_B in the sensing period is higher than the lowest gamma voltage V_min corresponding to the driving black data voltage Vdata_BD in the display period.

The black data voltage Vdata_B of the present invention can be set within a range that does not affect the sensing accuracy in a range higher than the drive black data voltage Vdata_BD. For example, the black data voltage Vdata_B of the sensing period can be set in the range of 1 to 5 [V]. The highest gamma voltage V_max (the highest gamma reference voltage RV'9 in the sensing period) corresponding to 255 gray levels in the sensing period is the highest gamma reference voltage RV9 in the display period (for example, 16 [ V]).

As described above, in the present invention, the gamma reference voltages of the gamma reference voltage generator 503 are changed during the sensing period, thereby changing the gamma voltages generated by the gamma voltage generator 504. In addition, the black data voltage Vdata_B supplied to the non-sensing sub-pixel is changed to be higher than the driving black data voltage Vdata_BD in the display period by using the changed gamma voltages. Thus, during the sensing period, the difference between the data voltage and the black data voltage (Vdata_B) in the non-sensing subpixel is reduced, thereby reducing the variation rate of the data voltage.

Therefore, in the present invention, the data voltage fluctuation of the non-sensing sub-pixels in the sensing period is reduced, thereby preventing a degradation of the screen quality in the display period in which the image is displayed.

8 is a view for explaining how a data voltage fluctuation in a non-sensing sub-pixel of an organic light emitting diode display of the present invention is reduced.

Referring to FIG. 8 together with FIG. 7, the organic light emitting display of the present invention supplies a sensing data voltage and a black data voltage (Vdata_B) higher than the driving black data voltage (Vdata_BD) to the sensing subpixel during a sensing period.

Also, during the sensing period, the non-sensing sub-pixels also supply a black data voltage (Vdata_B) higher than the driving black data voltage (Vdata_BD).

Therefore, the black data voltage (Vdata_B) supplied to the non-sensing subpixel during the sensing period is also supplied to the non-sensing subpixel to which the scan signal is not supplied (SCAN2: OFF voltage) as shown in FIG.

Thus, the black data voltage Vdata_B higher than the driving black data voltage Vdata_BD supplied to the non-sensing subpixel is supplied, and the difference between the data voltage VN2 of the second node and the black data voltage Vdata_B becomes equal to the driving black The data voltage Vdata_BD is reduced as compared to when the data voltage Vdata_BD is supplied.

For example, if the driving black data voltage Vdata_B in Fig. 4 is 0.5 [V] and the black data voltage Vdata_B in Fig. 8 is 3 [V], the data voltage VN2 of the non- The difference of the black data voltage Vdata_B is reduced by 2.5 [V], and the rate of variation of the data voltage Vdata of the non-sensing subpixel is reduced.

Therefore, the organic light emitting display device and the driving method thereof according to the present invention reduce the variation rate of the data voltage VN2 that has been held in the non-sensing subpixel to which no scan signal is supplied, .

FIG. 9 is an exemplary view of a display period and a sensing period of the organic light emitting diode display according to the present invention.

9, the sensing period for supplying the black data voltage (Vdata_B) higher than the driving black data (Vdata_BD) to the non-sensing subpixel may be a real sensing (RTS: Real Time Sensing Period).

More specifically, the sensing period may exist within a blank interval between display periods in which an image is displayed based on the vertical synchronization signal Vsync.

However, this is not fixed and can be performed in an off-sensing interval (OFFS) for sensing a threshold voltage or in an ON-sensing interval (ONS) for sensing a mobility and a real-time sensing interval (RTS).

As described above, in the present invention, a separate linear gamma curve corresponding to the sensing period for sensing the characteristics of the subpixel and the display period for displaying the image is generated, and the black data voltage supplied to the non- So that the variation of the data voltage generated in the non-sensing sub-pixel is minimized.

10 is a flowchart illustrating a method of driving an organic light emitting display according to the present invention.

Referring to FIG. 10, a method of driving an organic light emitting display according to the present invention includes steps S1001 and S1002 of determining whether a sensing period or a display period is performed by a sensing period checking unit disposed in a sensing period control unit, , The gamma reference voltages of the gamma reference voltage generator disposed in the OLED display are changed to change the gamma voltages generated by the gamma voltage generator to generate a linear gamma curve corresponding to the sensing period ).

(Vdata_B) higher than the driving black data voltage (Vdata_BD) used in the display period according to the sensing gamma curve (S1004) and supplies it to the sensing sub-pixel and the non-sensing sub- The drive proceeds (S1005).

On the other hand, if the sensing period is confirmed by the sensing section, the data voltage and the driving black data voltage (Vdata_BD) are generated according to the display gamut linear gamma curve generated by the predetermined gamma reference voltages to display an image S1006).

In the present invention, the gamma reference voltages are changed in order to raise the gamma voltage (gradation voltage) corresponding to the black data. However, by changing the black data value, the changed black data voltage according to the linear gamma curve of the display section To generate a voltage different from the driving black data voltage.

As described above, according to the OLED display and the driving method thereof, the black data voltage supplied to the sensing sub-pixel and the non-sensing sub-pixel during the sensing period is changed from the driving black data voltage supplied to the display period, It is possible to mitigate the fluctuation of the data voltage of the sensing subpixel, thereby preventing the deterioration of screen quality.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. , Separation, substitution, and alteration of the invention will be apparent to those skilled in the art. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

100: organic light emitting display
110: Display panel
120: Source driver
130: scan driver
140: Timing controller
500: sensing section control section
503: gamma reference voltage generator

Claims (7)

A display panel in which a plurality of data lines and a plurality of gate lines are arranged and a plurality of subpixels are arranged in a matrix type;
A source driver for driving the plurality of data lines;
A timing controller for controlling the source driver; And
And a gamma reference voltage generator for supplying a gamma reference voltage,
The source driver,
Generating gamma voltages corresponding to data supplied to the timing controller based on the gamma reference voltage,
Each of the plurality of sub-
An organic light emitting diode, and a driving transistor for driving the organic light emitting diode,
During a sensing period for sensing a characteristic value of the driving transistor,
The gamma reference voltage generator changes the gamma reference voltage,
The source driver generates and generates a black data voltage according to the changed gamma voltage by changing the gamma voltage for the black data corresponding to the subpixel based on the changed gamma reference voltage and supplies the black data voltage to the subpixel Organic light emitting display. The method according to claim 1,
Wherein the subpixel supplied with the black data voltage includes a sensing subpixel and a non-sensing subpixel,
The sensing sub-
A sensing data voltage for sensing a characteristic value of the driving transistor during the sensing period, and then receiving the black data voltage,
The non-sensing sub-
And the black data voltage is supplied during the sensing period. The method according to claim 1,
The gamma reference voltage generator changes the gamma reference voltage and the source driver changes the gamma voltage for the black data corresponding to the subpixel based on the changed gamma reference voltage, And a sensing period controller for controlling the OLED display to generate the OLED display. The method according to claim 1,
Wherein the gamma voltage for the black data in the sensing period is higher than the gamma voltage for the black data in the display driving period. A display panel in which a plurality of data lines and a plurality of gate lines are arranged and a plurality of subpixels are arranged in a matrix type;
A source driver for driving the plurality of data lines; And
And a timing controller for controlling the source driver, the driving method comprising:
Confirming whether the display panel is a display period for displaying an image or a sensing period for sensing a characteristic value of a driving transistor disposed in each subpixel;
Changing the gamma reference voltages based on the generation of the gamma voltages to change the gamma voltages for the black data corresponding to the subpixels,
Generating a black data voltage according to the changed gamma voltage and supplying the generated black data voltage to the subpixel. 6. The method of claim 5,
Wherein the subpixel supplied with the black data voltage includes a sensing subpixel and a non-sensing subpixel,
Supplying a sensing data voltage and a black data voltage for sensing the characteristic value of the sensing subpixel to the sensing subpixel during the sensing period,
And supplies the black data voltage to the non-sensing sub-pixel during the sensing period. 6. The method of claim 5,
Wherein the black data voltage in the sensing period is higher than the driving black data voltage in the display period.

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